This invention relates to a microchip for mixing two or more liquid, and a fluorescent particle counter with the microchip.
In various technical fields, number of particles has been counted after fluorescently staining. In a medical field, for instance, platelet products and erythrocyte products which are made by respectively extracting platelets and erythrocytes from blood are used. It is preferable that no leukocyte remains in platelet products and erythrocyte products. For this reason, leukocytes are removed in a process of producing. In order to confirm whether or not leukocytes have been removed from a platelet product or an erythrocyte product, number of leukocytes is counted (see a Japanese patent application (Publication No. 2001-83092, for instance).
FIG. 4 is a block diagram showing a structure of a conventional leukocyte counter. A reference number 100 of FIG. 4 denotes a container for containing fluorescently stained platelet product and the like, and a reference number 101 denotes a laser beam source through which laser beam irradiates the container 100. A reference number 102 denotes a mirror, and a reference number 103 is a CCD camera. When laser beam (excitation light) irradiates the container 100 through the laser beam source 101 in such a counter, an image of leukocytes is obtained by the CCD camera 103. This image is captured in a computer (not shown) and is processed, and then, the number of the leukocytes is counted.
In order to fluorescently stain particles to be counted, it is necessary to mix fluorescent dyes into solution including particles. In order to fluorescently stain leukocytes in a platelet product, for instance, it is necessary to mix fluorescent dyes, such as propidium iodide, and a platelet product (concretely speaking, bare nuclei of leukocytes after platelets and erythrocytes are removed with surfactant, such as Triton X-100).
A machine for mixing two or more liquid (a microchip), which is not produced for a purpose of fluorescent particle counting, having a structure as shown in FIG. 5, has been proposed (see both Japanese patent applications (publication Nos. 2002-221485, 2003-181255), for instance). A reference number 200 in the figure denotes a specimen supply port for supplying liquid specimen, and a reference number 201 denotes a passage thereof. A reference number 202 denotes a reagent supply port for supplying liquid reagent, and a reference number 203 is a passage thereof. Specimen and reagent which are supplied through both supply ports 200, 202 meet together at a meeting portion 204 and are mixed, and drained from an exit 206 via an outflow passage 205.
In order to fluorescently stain particles, it is necessary to sufficiently mix fluorescent dyes into solution including particles. When fluorescently staining leukocytes with fluorescent dyes, for instance, propidium iodide or ethidium bromide, it is necessary to intercalate fluorescent dyes between bases of DNA of nuclei of leukocytes, and it is necessary to sufficiently mix. If particles are counted with a counting unit as shown in FIG. 4 after mixing fluorescent dyes with a structure as shown in FIG. 5, but, the counting accuracy of the particles is not good due to insufficient fluorescently staining. In order to remove platelets and erythrocytes and to obtain bare nuclei of leukocytes, it is necessary to sufficiently mix surfactant so as to react. But, in the structure as shown in FIG. 5, platelets and cell membranes of leukocytes remain due to insufficient mixing, so that the counting accuracy of leukocytes is made bad.
Besides, with the counting unit as shown in FIG. 4, an operation of entering of a fluorescently stained platelet product and the like into the container 10, a processing of rotation of the container 100 in order to fix fluorescent particles on a bottom of the container (centrifugation), and an operation of tracing (specifically determining) specimen in the container 100 are necessary, so that the counting operations are made complex.
Furthermore, it is necessary to switch an optical path according to concentration of specimen to be measured in case of the counting unit as shown in FIG. 4. For this reason, the counting operation is made more complex, and the structure of the unit is made complex.
Under these circumstances, a microchip for sufficiently mixing two or more liquid, and a fluorescent particle counter where a counting operation is simple have been desired.